JP6828597B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

In low-priced image forming devices such as conventional general-purpose printers, electromagnetic clutches are often used in order to reduce costs as a drive transmission and cutoff mechanism to a transfer roller. In such a configuration, if an abnormality or failure occurs in the electromagnetic clutch, paper transfer jam or image position shift occurs. Therefore, a technique for attaching an encoder to the paper transfer roller and determining the state of the electromagnetic clutch from the rotation speed of the transfer roller. Is already known.

As an example of the above-mentioned technique, for the purpose of inspecting the electromagnetic clutch, there is a technique of estimating the coupling time of the electromagnetic clutch from the signal of the encoder attached to the paper transport roller that drives and shuts off the drive by the electromagnetic clutch. For example, see "Patent Document 1").

However, in the conventional electromagnetic clutch inspection technique, it is necessary to attach an encoder to the paper transport roller, which has problems of cost increase and an increase in size of the device.
In addition, an image forming apparatus that does not have electromagnetic clutch inspection technology has a problem that a failure of the electromagnetic clutch cannot be predicted in advance, and when a problem occurs in the electromagnetic clutch, the repairer can reach a normal electromagnetic clutch. There was a problem of increased downtime and cost increase due to replacement.

The present invention solves the above-mentioned problems, can inspect the state of the electromagnetic clutch, can predict a failure in advance and reduce downtime, and can achieve low cost and miniaturization of the device. The purpose is to provide a forming device.

The invention according to claim 1 comprises a transport means for transporting a medium to be transported, a drive means for driving the transport means, a drive transmission member for transmitting and blocking a driving force from the drive means to the transport means, and the like. It has a current detecting means for detecting the current value of the driving means, and when the driving means is operated from the state in which the driving means is on and the driving force is transmitted to the conveying means, the current value becomes the first. The drive connection time of the drive transmission member is estimated from the first time exceeding the threshold value of 1, and when the drive connection time exceeds the first predetermined value, it is determined that the drive transmission member is operating abnormally. It is characterized by.

According to the present invention, it is possible to predict in advance a failure of each drive transmission member without using a new configuration such as an encoder, and down due to a failure of each drive transmission member without causing an increase in cost and an increase in size of the device. The generation of time can be reduced.

It is a schematic front view of the image forming apparatus to which one Embodiment of this invention is applied. It is a schematic diagram explaining the drive means, the drive transmission member, and the transport means used in one Embodiment of this invention. It is a block diagram of the control means used in one Embodiment of this invention. It is the schematic explaining the control operation in 1st Embodiment of this invention. It is a flowchart explaining the control operation in 1st Embodiment of this invention. It is the schematic explaining the control operation in 2nd Embodiment of this invention. It is the schematic explaining the control operation in 3rd Embodiment of this invention.

FIG. 1 shows a color printer as an image forming apparatus to which one embodiment of the present invention can be applied. In the figure, the printer 1 has four image forming units 2Y, 2C, 2M, 2Bk, a primary transfer unit 3, a secondary transfer roller 4, an optical writing device 5, a paper feeding device 6, and fixing inside the apparatus main body 1a. It has a device 7, a paper ejection roller pair 8, a switching plate 9, a reversing transfer unit 10, a paper ejection tray 11, and the like.

The image forming portions 2Y, 2C, 2M, and 2Bk arranged substantially in the center of the apparatus main body 1a correspond to a yellow image, a blue image, a red image, and a black image, respectively, and the photoconductor drum 12Y, which is an image carrier, respectively. It has 12C, 12M, 12Bk, a charging roller 13Y, 13C, 13M, 13Bk, a developing device 14Y, 14C, 14M, 14Bk, a photoconductor cleaning device 15Y, 15C, 15M, 15Bk and the like. The surfaces of the photoconductor drums 12Y, 12C, 12M, and 12Bk are exposed by the optical writing device 5, and electrostatic latent images corresponding to the formed images are formed. The formed electrostatic latent image is visualized by each color toner supplied from each toner bottle 16Y, 16C, 16M, 16Bk to each corresponding developing apparatus 14Y, 14C, 14M, 14Bk.

A primary transfer unit 3 is arranged above each image forming unit 2Y, 2C, 2M, 2Bk. The primary transfer unit 3 includes the photoconductor drums 12Y, via the intermediate transfer belt 22 and the intermediate transfer belt 22 hung on the inlet roller 17, the drive roller 18, the cleaning opposing roller 19, the backup roller 20, and the support roller 21. It has primary transfer rollers 23Y, 23C, 23M, 23Bk and the like arranged at positions facing 12C, 12M, 12Bk. Toner images corresponding to each color are superimposed and transferred from the photoconductor drums 12Y, 12C, 12M, and 12Bk on the surface of the intermediate transfer belt 22.

A secondary transfer roller 4 is arranged at a position facing the drive roller 18 via the intermediate transfer belt 22. The secondary transfer roller 4 forming the secondary transfer nip portion together with the drive roller 18 has a transfer belt for the paper P fed from the paper feed device 6 by applying a bias by a bias applying means (not shown). The toner image superimposed and transferred on the surface of 22 is collectively transferred.
An optical writing device 5 is arranged below each image forming unit 2Y, 2C, 2M, 2Bk. The optical writing device 5 has a well-known configuration having a light source (not shown), a polygon mirror, various mirrors, a lens, and the like, and an electrostatic latent image corresponding to an externally input image is generated on each photoconductor drum 12Y, 12C, 12M, 12Bk. It is formed on the surface of each.

The paper feed device 6 arranged at the lower part of the apparatus main body 1a includes a paper feed tray 24 for loading the paper P as a medium to be conveyed, a calling roller 25 and a paper feed roller 26 for feeding the paper P from the paper feed tray 24, and a feed roller 26. A friction pad 27 that separates and feeds the paper P in cooperation with the paper roller 26, a paper transport roller pair 28, a resist roller pair 29, a manual feed tray 30, a second paper feed roller 31 that feeds the paper P from the manual feed tray 30, a second. 2. It has a second friction pad 32 that separates and feeds the paper P in cooperation with the paper feed roller 31, a paper transport roller pair 33, and the like.

The paper feed tray 24 arranged at the bottom of the device main body 1a is configured to be able to be pulled out to the right in the drawing when the cover member 1b supported to be opened and closed by the device main body 1a is opened. A large number of sheets P are loaded on the upper surface thereof. A calling roller 25 and a paper feed roller 26 are arranged above the paper feed tray 24 so as to come into contact with the loaded top-level paper P. The rollers 25 and 26 are rotationally driven in the same direction by a driving means (not shown). The friction pad 27 made of a high friction resistance member such as rubber is pressure-welded to the peripheral surface of the paper feed roller 26 by the urging force of the spring 27a.

Both the paper transport roller pair 28 have a drive roller and a driven roller rotatably supported by the apparatus main body 1a, and the driven roller is rotationally driven by a driving means (not shown) to rotate the driven roller pressed against the drive roller. Then, the paper P is conveyed. The resist roller pair 29 arranged on the downstream side of the paper transport roller pair 28 in the paper transport direction also has a drive roller and a driven roller rotatably supported by the apparatus main body 1a, and is driven by a drive means (not shown). Is rotated to convey the paper P to the downstream side at a predetermined timing.

The manual feed tray 30 is supported by the cover member 1b so as to be openable and closable, and the paper P is loaded on the upper surface thereof in the opened state. The second paper feed roller 31 is also rotatably supported by the cover member 1b, and separates the paper P on the bypass tray 30 in cooperation with the second friction pad 32 which is supported by the cover member 1b and press-contacts the peripheral surface thereof. Send. The paper transport roller pair 33 both have a drive roller and a driven roller rotatably supported by the cover member 1b, and the driven roller is rotationally driven by a driving means (not shown) to rotate the driven roller in contact with the drive roller. Then, the paper P is conveyed. The cover member 1b is rotatably supported by the secondary transfer roller 4 described above and the pressure roller 35 described later, respectively, and is configured so that the transport path of the paper P is opened when the cover member 1b is opened. ing.

The fixing device 7 arranged on the downstream side of the secondary transfer roller 4 in the paper transport direction has a heating roller 34 and a pressure roller 35, and is arranged above the device main body 1a. The heating roller 34 having a heat source (not shown) is rotatably supported by the apparatus main body 1a, and is rotationally driven by a driving means (not shown). The pressure roller 35 rotatably supported by the cover member 1b has its peripheral surface pressed against the peripheral surface of the heating roller 34 by the urging force of an urging means (not shown), and rotates together with the heating roller 34. The paper P passing between the rollers 34 and 35 is fixed with a toner image formed on the upper surface by the heat and pressure thereof.

The paper ejection roller pair 8 arranged on the downstream side in the paper transport direction of the fixing device 7 both has a drive roller and a driven roller rotatably supported by the device main body 1a, and are driven by a drive means (not shown). As the paper P rotates, the driven roller pressed against the paper P rotates and discharges the paper P to the outside of the apparatus main body 1a. The paper P ejected by the output roller pair 8 is loaded on the output tray 11 integrally formed on the upper surface of the apparatus main body 1a.

A switching plate 9 is arranged at a position immediately upstream of the paper ejection roller pair 8 in the paper transport direction. The switching plate 9 selectively occupies the first position shown by the solid line and the second position shown by the alternate long and short dash line in FIG. 1 by a switching means (not shown) such as a solenoid. When the switching plate 9 occupies the first position, the paper P is guided to the paper ejection roller pair 8, and when the switching plate 9 occupies the second position, the paper P is guided to the reversing transport unit 10.

A reversing transfer portion 10 is provided inside the cover member 1b and located on the right side of the secondary transfer roller 4 and the pressure roller 35. The reversing transfer unit 10 has a reversing roller pair 36, a paper transport roller pair 37, 38, and the like. The reverse roller pair 36 arranged on the downstream side of the switching plate 9 in the paper transport direction has a drive roller 36a and a driven roller 36b. The drive roller 36a is rotatably supported by the device main body 1a, and is rotationally driven in the forward and reverse directions by a drive means (not shown). When the drive roller 36a rotates in the forward direction, the paper P is sent to the outside of the device main body 1a, and when the drive roller 36a rotates in the reverse direction, the paper P is sent to the inside of the device main body 1a. The driven roller 36b is rotatably supported by the cover member 1b, and its peripheral surface is pressed against the peripheral surface of the driving roller 36a by the urging force of an urging means (not shown). Both the paper transport rollers 37 and 38 have a drive roller and a driven roller rotatably supported by the cover member 1b, respectively, and the driven rollers are rotationally driven by a driving means (not shown) to press-contact the driven rollers. The rollers rotate to convey the paper P downward.

From the above configuration, when forming an image on one side of the paper P, the paper P separated and fed from the paper feed tray 24 is conveyed by the paper transfer roller pair 28 and the resist roller pair 29, and is conveyed by the secondary transfer roller 4. The toner image corresponding to the surface image is transferred to one of the surfaces (the surface on the left side in FIG. 1). After the toner image is fixed when the paper P on which the toner image is transferred passes through the fixing device 7, the paper P is guided to the paper ejection roller pair 8 by the switching plate 9 occupying the first position, and is guided to the paper ejection roller pair 8. Discharged onto 11.

When forming an image on both sides of the paper P, the paper P on which the toner image is transferred to one surface by the secondary transfer roller 4 is fixed to the toner image when passing through the fixing device 7, and then the second sheet P is formed. It is guided to the reverse roller pair 36 by the switching plate 9 occupying the position of. At this time, the reverse roller pair 36 is rotating forward, and the paper P is sent to the outside of the apparatus main body 1a. Then, when the rear end of the paper P reaches the reversing roller pair 36, the reversing roller pair 36 is reversed, the paper P is sent from the rear end side to the inner side of the apparatus main body 1a, and the paper transport roller pair 37, 38, 33. Is sent to the resist rollers vs. 29 via. At this time, the other surface of the paper P is in a positional relationship facing the transfer belt 22, and the toner image corresponding to the back surface image is transferred to the other surface of the paper P by the secondary transfer roller 4. After the toner image is fixed when the paper P on which the toner image is transferred passes through the fixing device 7, the paper P is guided to the paper ejection roller pair 8 by the switching plate 9 occupying the first position, and is guided to the paper ejection roller pair 8. Discharged onto 11.

Below the device main body 1a, a bank paper feeding device 39 attached to the device main body 1a is arranged so that the upper surface of the device main body 1a is in contact with the bottom surface of the device main body 1a. Similar to the paper feed device 6, the bank paper feed device 39 includes a bank paper feed tray 40 for loading paper P, a bank call roller 41 for feeding paper P from the bank paper feed tray 40, a bank paper feed roller 42, and a bank paper feed roller 42. It has a bank friction pad 43 for separately feeding paper P in cooperation with 42, a bank transfer roller pair 44, and the like. The bank paper feed device 39 constitutes the color printer 1 by being integrally configured with the device main body 1a.

Among the color printers 1 described above, the paper feed roller 26, the resist roller pair 29, and the bank paper feed roller 42 function as transport means for transporting the paper P which is the transfer medium in the present invention. The configuration of the paper feed roller 26, the resist roller pair 29, and the bank paper feed roller 42 will be described with reference to FIG.
As shown in FIG. 2, the paper feed roller 26, the resist roller pair 29, and the bank paper feed roller 42 are rotationally driven by a drive motor 45, which is a single drive means. The calling roller 25 and the paper transfer roller pair 28, and the bank calling roller 41 and the bank transfer roller pair 44 are respectively transmitted with the driving force from the paper feed roller 26 and the bank paper feed roller 42 by a driving force transmitting means (not shown). They are rotationally driven in synchronization with the paper feed roller 26 and the bank paper feed roller 42, respectively.

The drive motor 45 fixed to the device main body 1a has a pinion 46 on its output shaft, and the pinion 46 is located on the large diameter portion of the first gear 47, which is a two-stage gear rotatably supported by the device main body 1a. It is in mesh. Further, the large diameter portion of the first gear 47 meshes with the idle gear 48 rotatably supported by the apparatus main body 1a, and the idle gear 48 is a second gear rotatably supported by the apparatus main body 1a. It meshes with the large diameter portion of the gear 49.

The small diameter portion of the first gear 47 meshes with the resist gear 50 provided coaxially with the drive roller of the resist roller pair 29, and the drive motor 45 connects the resist gear 50 and the drive gear of the resist roller pair 29. A first electromagnetic clutch 51 is provided as a drive transmission member for transmitting and interrupting the driving force of the above from the resist gear 50 to the drive gear of the resist roller pair 29.

Further, the small diameter portion of the first gear 47 meshes with the paper feed gear 52 provided coaxially with the paper feed roller 26, and the paper feed gear 52 and the paper feed roller 26 are connected from the drive motor 45. A second electromagnetic clutch 53 is provided as a drive transmission member that transmits and shuts off the driving force from the paper feed gear 52 to the paper feed roller 26.

The small diameter portion of the second gear 49 meshes with the bank paper feed gear 54 provided coaxially with the bank paper feed roller 42, and a drive motor is provided between the bank paper feed gear 54 and the bank paper feed roller 42. A third electromagnetic clutch 55 is provided as a drive transmission member that transmits and shuts off the driving force from the 45 to the bank paper feed roller 42 from the bank paper feed gear 54.
The small diameter portion of the second gear 49 and the bank feeding gear 54 are configured to mesh with each other when the bank feeding device 39 is connected to a predetermined position with respect to the device main body 1a.

FIG. 3 shows a block diagram of the control means used in one embodiment of the present invention. The control means 56, which is attached to the device main body 1a and is composed of a well-known microcomputer having a CPU, ROM, RAM, etc., controls the operation of the motor control device 56a and the first electromagnetic clutch 51 that control the operation of the drive motor 45 inside the control means 56. From the current values of the clutch control device 56b, the clutch control device 56c that controls the operation of the second electromagnetic clutch 53, the clutch control device 56d that controls the operation of the third electromagnetic clutch 55, and the drive motor 45, each clutch 51, 53, It has a transmission / interruption time comparison device 56e for estimating the transmission and interruption time of 55.
A current detector 57 as a current detecting means for detecting the current value of the drive motor 45 and a display device 58 functioning as a notification means are connected to the control means 56, and the control means 56 is connected to the control means 56 from the current detector 57. The detection result is input. The display device 58 displays various information and the like when an abnormality occurs in the color printer 1.

Based on the above configuration, the operation of the color printer 1 will be described below.
When a start key on an operation panel (not shown) provided on the apparatus main body 1a is pressed, a well-known image forming operation is performed in each image forming unit 2 to form an electrostatic latent image on each photoconductor drum 12. To. Each of the formed electrostatic latent images is developed by each developing device 14, and each color toner image is formed on each photoconductor drum 12. The formed color toner images are superimposed and transferred on the intermediate transfer belt 22 by the primary transfer rollers 23, and a full-color image is formed on the intermediate transfer belt 22.

The paper P is fed from either the paper feed tray 24 or the bank paper feed tray 40 selected on the operation panel (not shown) in accordance with the image forming operation described above. When the paper feed tray 24 is selected, the second electromagnetic clutch 53 is operated from the state in which the drive motor 45 is operating, and the driving force of the drive motor 45 is transmitted to the calling roller 25 and the paper feed roller 26 to be transmitted to each roller. The 25 and 26 are rotationally driven, and the paper P is fed from the paper feed tray 24. The fed paper P is prevented from being double-fed by the friction pad 27, and is fed to the resist roller pair 29 via the paper transport roller pair 28 in a state of being separated into one sheet. One sheet of paper P sent is suspended at the nip portion of the resist roller pair 29.
When the bank paper feed tray 40 is selected, the third electromagnetic clutch 55 operates from the state in which the drive motor 45 is operating, and the driving force of the drive motor 45 is applied to the bank calling roller 41 and the bank paper feed roller 42. Each of the rollers 41 and 42 is rotationally driven by the transmission, and the paper P is fed from the bank paper feed tray 40. The fed paper P is prevented from being double-fed by the bank friction pad 43, and is fed to the resist roller pair 29 via the bank transport roller pair 44 and the paper transport roller pair 28 in a state of being separated into one sheet.

After that, the first electromagnetic clutch 51 operates at the same timing as the full-color image on the intermediate transfer belt 22, the driving force of the drive motor 45 is transmitted to the resist roller pair 29, and the resist roller pair 29 is rotationally driven. The paper P temporarily stopped by this rotation is fed to the secondary transfer nip portion, and the full-color image formed on the intermediate transfer belt 22 at the secondary transfer nip portion is collectively transferred onto the paper P. The paper P on which the full-color image is transferred is sent to the fixing device 7, and after the full-color image is fixed by heat and pressure, the paper P is discharged onto the output tray 11 by the output roller pair 8.

Here, the control operation of the control means 56 according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG.
First, the electromagnetic clutches 51, 53, 55 are operated while the drive motor 45 is operating, the driving force of the drive motor 45 is transmitted to the rollers 26, 29, 42, which are the transport means, and the drive motor is driven. The current value of 45 is detected by the current detector 57 (ST01). At this time, as shown in FIG. 4, the current value of the drive motor 45 increases as the load on the drive motor 45 increases.

The control means 56 estimates the drive connection time C of the electromagnetic clutches 51, 53, 55 from the first time B until the current value of the drive motor 45 detected by the current detector 57 exceeds the first threshold value A. (ST02). Then, the control means 56 determines whether or not the estimated drive connection time is within the preset first predetermined value D (ST03). Here, when the estimated drive connection time exceeds the first predetermined value D as in the drive connection time E shown by the alternate long and short dash line in FIG. 4, it is determined that the electromagnetic clutch is operating abnormally, and the number of times. Is recorded in a storage means (not shown) (ST04).

When the control means 56 determines in step ST03 that the electromagnetic clutch has an abnormality, the control means 56 confirms whether or not a paper transport jam has occurred at the location of the electromagnetic clutch where the abnormality has occurred (ST05). Here, if the estimated drive connection time exceeds the first predetermined value D but the paper transport jam has not occurred, the operator of the color printer 1 is notified via the display device 58 to that effect. Then, the image forming operation is continued (ST07).

If the estimated drive connection time exceeds the first predetermined value D and a paper transport jam has occurred, whether or not the control means 56 can continue the image forming operation without using the corresponding electromagnetic clutch. (ST06). If the image forming operation can be continued, for example, if an abnormality has occurred in the second electromagnetic clutch 53 but no abnormality has occurred in the third electromagnetic clutch 55, the bank without operating the paper feed roller 26 The paper feed roller 42 is driven to feed paper from the bank paper feed tray 40 to continue the image forming operation (ST07).
If the image forming operation cannot be continued, for example, if an abnormality has occurred in the first electromagnetic clutch 51, the operator of the color printer 1 is notified via the display device 58 to that effect and the image forming operation is performed. Is canceled (ST08).

As described above, in the present invention, when the driving motor 45 is turned on and the electromagnetic clutches 51, 53, 55 are operated to transmit the driving force of the driving motor 45 to the rollers 26, 29, 42, the current is detected. The drive connection time of each electromagnetic clutch 51, 53, 55 is estimated from the first time B when the current value of the drive motor 45 detected by the device 57 exceeds the first threshold value A, and the estimated drive connection time is the first. When the predetermined value D is exceeded, it is determined that the electromagnetic clutches 51, 53, 55 are malfunctioning.
With this configuration, it is possible to predict the failure of each electromagnetic clutch in advance without using a new configuration such as an encoder, and it is possible to prevent downtime due to the failure of each electromagnetic clutch without increasing the cost and increasing the size of the device. It can be reduced.

Next, the control operation of the control means 56 according to the second embodiment of the present invention will be described.
When the electromagnetic clutches 51, 53, 55 are operated to drive off the driving force of the drive motor 45 from the rollers 26, 29, 42, the drive motor is reduced by reducing the load on the drive motor 45, as shown in FIG. The current value of 45 decreases. The control means 56 starts the electromagnetic clutch from the second time G until the current value of the drive motor 45 detected by the current detector 57 after operating the electromagnetic clutches 51, 53, 55 falls below the second threshold value F. The drive cutoff time H of 51, 53, 55 is estimated.
Then, when the estimated drive cutoff time exceeds a preset second predetermined value I such as the drive cutoff time J shown by the alternate long and short dash line in FIG. 6, the electromagnetic clutch operates abnormally. The number of times is recorded in a storage means (not shown).

The control means 56 confirms whether or not a paper transport jam has occurred at the location of the electromagnetic clutch where the abnormality has occurred. Here, if the estimated drive cutoff time exceeds the second predetermined value I but the paper transport jam has not occurred, the operator is notified via the display device 58 to perform the image forming operation. continue.
When the estimated drive cutoff time exceeds the second predetermined value I and a paper transport jam has occurred, whether or not the control means 56 can perform the image forming operation without using the corresponding electromagnetic clutch. To judge. If the image forming operation can be continued, the image forming operation is continued, and if the image forming operation cannot be continued, the operator is notified via the display device 58 to that effect and the image forming operation is stopped. To do.
Also in this second embodiment, the same effect as that of the first embodiment can be obtained.

In each of the above-described embodiments, when an abnormality occurs in the operation of the electromagnetic clutch, the control means 56 records the number of times, so that the serviceman can determine the state of the color printer 1 from the recorded number of times, which is appropriate. Can be dealt with.
Further, when an abnormality occurs in the operation of the electromagnetic clutch, the operator of the color printer 1 is notified via the display device 58, so that the device can be dealt with before the device malfunctions and the device malfunctions. This makes it possible to prevent an increase in downtime.
Further, when an abnormality occurs in the operation of the electromagnetic clutch and a paper transport jam occurs in the peripheral portion of the transport roller corresponding to the electromagnetic clutch, the control means 56 is connected to the electromagnetic clutch. Since the use of the transfer roller is prohibited, the occurrence of downtime can be reduced. Further, if there is a usable electromagnetic clutch and transfer roller, the driving force is transferred to them, so that the image forming operation can be continuously performed.

In each of the above embodiments, the first predetermined value D and the second predetermined value I may be configured to have two or more numerical values. With this configuration, in the case of a model in which the paper spacing changes depending on the paper type, the allowable delay time in the drive connection time and drive cutoff time changes. Therefore, no matter what paper type is used. However, it is possible to provide an image forming apparatus capable of determining the state of the electromagnetic clutch using an optimum predetermined value and continuously performing a good image forming operation.

The color printer 1 described above may have an inspection mode for each electromagnetic clutch that is a drive transmission member. This inspection mode is activated during the non-image forming operation by pressing a key arranged on an operation panel (not shown) provided on the apparatus main body 1a.
Specifically, the inspection mode key is pressed before the image forming operation is performed, and the inspection mode is started. In the inspection mode, each electromagnetic clutch is operated from the state in which the drive motor 45 is operating, and the drive transmission time and drive from the drive motor for each transfer roller are as in the first embodiment and the second embodiment. The cutoff time is estimated, and it is determined whether or not the drive transmission time and the drive cutoff time are within the preset predetermined values.
With this configuration, the inspection of the electromagnetic clutch can be easily performed. It is desirable that this inspection mode be included in the serviceman program so that it cannot be easily performed by a user other than the serviceman.

Next, a third embodiment of the present invention will be described. In each of the first and second embodiments described above, when the electromagnetic clutches 51, 53, 55 are operated before the drive motor 45 is driven, an abnormality cannot be detected. Therefore, the abnormality detection of each of the electromagnetic clutches 51, 53, 55 when the electromagnetic clutches 51, 53, 55 are operated before the drive of the drive motor 45 will be described as the third embodiment.

In the third embodiment, as shown in FIG. 7, after the motor current stabilizes, for example, after the rise time, the current value of the drive motor 45 is detected by the current detector 57, and the detected value is preset. The abnormality of the electromagnetic clutches 51, 53, 55 can be detected depending on whether the threshold value K is higher or lower than the threshold value K of 3.
When the electromagnetic clutches 51, 53, and 55 are operated to perform drive transmission, if the detected current value is equal to or higher than the third threshold value K and falls below it, it is determined to be abnormal.
When the electromagnetic clutches 51, 53, and 55 are operated to shut off the drive, it is determined that the detected current value is normal when the detected current value is equal to or less than the third threshold value K, and it is determined that the electromagnetic clutch is abnormal.

According to this third embodiment, the abnormality of the electromagnetic clutches 51, 53, 55 can be detected even when the electromagnetic clutches 51, 53, 55 are operated before the drive motor 45 is driven. , The same action and effect as those of the first and second embodiments can be obtained.
Further, when the drive motor 45 is turned on with the electromagnetic clutches 51, 53, 55 turned off, the electromagnetic clutches 51, 53, 55 are abnormal even when the detected current value exceeds the third threshold value K. It can be determined that there is.

In the above embodiment and each modification, an example in which a color printer is used as an image forming apparatus is shown, but the image forming apparatus is not limited to this, and other types of printers, facsimiles, copying apparatus, multifunction devices, etc. are also used. The present invention is applicable. Further, in the present embodiment and the modified example, the configuration in which the paper P is used as the conveyed medium to be conveyed by the conveying means is shown, but the paper P is not limited to the recording paper, and is thick paper, postcard, envelope, plain paper. , Thin paper, coated paper (coated paper, art paper, etc.), tracing paper, etc. are also included. Further, as a recording medium other than paper, any substance such as an OHP sheet, an OHP film, and a resin film, which has a sheet shape and can form an image, may be used.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and unless otherwise specified in the above description, the present invention described in the claims. Various modifications and changes are possible within the scope of the purpose.
The effects described in the embodiments of the present invention merely exemplify the most preferable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not it.

1 Image forming device (color printer)
26 Transport means (paper feed roller)
29 Transport means (resist roller pair)
42 Transport means (bank paper feed roller)
45 Drive means (drive motor)
51 Drive transmission member (first electromagnetic clutch)
53 Drive transmission member (second electromagnetic clutch)
55 Drive transmission member (third electromagnetic clutch)
56 Control means 57 Current detection means (current detector)
58 Notification means (display device)
A 1st threshold value B 1st time C Drive connection time D 1st predetermined value F 2nd threshold value G 2nd time H Drive cutoff time I 2nd predetermined value K 3rd threshold value P Transport medium ( Paper)

Japanese Unexamined Patent Publication No. 2005-194037

Claims (9)

A transport means for transporting the medium to be transported and
The driving means for driving the transporting means and
A drive transmission member that transmits and cuts off the driving force from the driving means to the conveying means.
It has a current detecting means for detecting the current value of the driving means, and has
When the drive transmission member is operated from the state in which the drive means is on and the drive force is transmitted to the transfer means, the drive transmission member is driven from the first time when the current value exceeds the first threshold value. An image forming apparatus having a control means for estimating a connection time and determining that the drive transmission member is operating abnormally when the drive connection time exceeds a first predetermined value. In the image forming apparatus according to claim 1,
An image forming apparatus having two or more of the first predetermined values. A transport means for transporting the medium to be transported and
The driving means for driving the transporting means and
A drive transmission member that transmits and cuts off the driving force from the driving means to the conveying means.
It has a current detecting means for detecting the current value of the driving means, and has
When the drive transmission member is operated from the state in which the drive means is on to interrupt the transmission of the drive force to the transfer means, the drive transmission member starts from a second time when the current value falls below the second threshold value. An image forming apparatus having a control means for estimating a drive cutoff time of the above and determining that the drive transmission member is operating abnormally when the drive cutoff time exceeds a second predetermined value. In the image forming apparatus according to claim 3,
An image forming apparatus having two or more of the second predetermined values. In the image forming apparatus according to any one of claims 1 to 4.
An image forming apparatus, characterized in that the control means records the number of times when the drive transmission member is determined to be abnormal in operation. In the image forming apparatus according to any one of claims 1 to 5.
An image forming apparatus comprising a notification means for notifying an operator when it is determined that the drive transmission member has an operation abnormality. In the image forming apparatus according to any one of claims 1 to 6.
When it is determined that the drive transmission member is operating abnormally and a transfer failure of the conveyed medium occurs in the peripheral portion of the transfer means corresponding to the drive transmission member, the control means controls the drive transmission member. An image forming apparatus comprising prohibiting the use of the transport means connected to the image forming means. In the image forming apparatus according to any one of claims 1 to 7.
Except during the image forming operation, the drive transmission member is operated from the state in which the drive means is on to transmit the drive force to the transfer means, or the drive transmission member is operated from the state in which the drive means is on. An image forming apparatus comprising an inspection mode of the driving transmission member for blocking transmission of the driving force to the conveying means. A transport means for transporting the medium to be transported and
The driving means for driving the transporting means and
A drive transmission member that transmits and cuts off the driving force from the driving means to the conveying means.
It has a current detecting means for detecting the current value of the driving means, and has
When the drive means is operated from the state in which the drive transmission member is on and the drive force is transmitted to the transfer means, and the current value after a lapse of a predetermined time falls below the third threshold value, the drive transmission is performed. An image forming apparatus having a control means for determining that a member is malfunctioning.

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